Quaternary ammonium salts of dibenzthiazyl azo benzenes



Patented Feb. 24, 1948 QUATERNARY AMMONEUM SALTS OF EL BENZTHIAZYL AZO BENZENES No Drawing. Application Apr-i113, 19 15, Serial No. 588,239. In Great Britain May 8, 1944 6 Claims. (01. 260158) The present invention relates to the manufacture of new yellow azo dyestuffs and in particular to such dyestufis which are quaternary ammonium salts derived from 4:4-dibenzthiazyl (2)-azobenzene and are suitable for dyeing cellulosic material.

We have found that if 4:4'-di(6-methylbenzthiazyl-2)-azobenzene carrying at least one chloromethyl group as substituent is allowed to react with pyridine, a quaternar ammonium salt is formed. This salt dissolves readily in water to form a yellow solution which dyes cotton yellow. In carrying out such a dyeing, it is advantageous that there be present in the dyebath a mild alkali, for instance, sodium carbonate. In this way bright yellow shades are obtained which possess excellent fastness to washing. In place of pyridine other tertiary bases may be employed as indicated below.

Accordingly, the present invention relates to a process for the manufacture of new yellow azo dyestufis which comprises heating a 4:4- dibenzthiazyl-(2) -azobenzene which has directly substituted in it at least one chloromethyl group, and may optionally carry one or more halogen alkyl (1-40) or alkoxy (1-40) substituents, with a tertiary base.

Examples of starting materials for use in this invention include di(chloromethyl) -4= l'-di (6- methylbenzthiazyl 2) azobenzene (made by treating 4:4'-di(6 methylbenzthiazyl 2) azobenzene with sym. dichlorodimethyl ether), di- (chloromethyl) -4:l-di(benzthiazyl 2) -azobenzene, di(chloromethy1) 4:4 di(6 ethoxybenzthiazyl 2) azobenzene and di(chloromethyl)- 4 4'-di 6-methylbenzthiazyl-2) -azobenzene.

The tertiary bases to be used in accordance with the present invention include, for instance: pyridine, hexahydrodimethyl-aniline, triethylamine, triethanolamine, tetra methylthiourea, diethylaminoethyl alcohol.

The present dyestuffs appear to be, as already indicated above, quaternary ammonium salts. They dye cotton in bright yellow shades, advantageously from a dyebath containing a mild al kali, such as sodium carbonate or sodium bicarbonate. The use of the present new dyestuffs in such a dyebath, namely one containing a mild alkali, constitutes a further feature of the present invention.

The yellow shades obtained upon cotton by means of the present dyestuffs possess very good fastness to washing, open soda boiling and soda ash treatment, equalling in these respects dyein s of Caledon Yellow G (Colour Index No.

Norman Hulton Haddock and Clifford Wood,

England, assignors to 1241). Their fastness to light is also very good. The following examples in which the parts are by weight, iIlustrate but do not limit the invention.

Ezzzample 1 12 parts of chloromethylated 4:4'-di(6-methylbenzthiazyl-Z)-azobenzene (made as described below) are mixed with 150 parts of pyridine. The resulting suspension is boiled for 10 min utes. It turns bright yellow as the quaternary ammonium saltis produced. After dilution with twice its volume of acetone, the suspension is filtered. The filter cake iswashed withacetone to remove pyridine, and dried in air. The new quaternary ammonium salt is thus obtained as a bright yellow powder.

The chloromethylated 4:4'-di(6-methylbenzthiazyl-2)-azobenzene employed above is made as follows: 10 parts of 4:4"-di(6-methylbenzthiazyl-2)azobenzene are dissolved in 150 parts of 100% sulphuric acid below 30 C. and 50 parts of symmetrical dichlorodimethyl ether are added. The mixture is quickly heated to C. and maintained at this temperature for 20 minutes. The red solution obtained is poured on to 100 parts of a mixture of ice and water, filtered and the filter cake washed with Water till free of acid. The product is dried in the air. 12 parts of a pale yellow powder are obtained.

A dyebath is made by dissolving 1 part of this dyestuff in 1500 parts of water. 50 parts of bleached cotton yarn are put into the dyebath. The temperature is raised to 60 C. and maintained thereat. Thrice, at 10-minute intervals, after the temperature of 60 C. has been attained, 1 part of soda ash is added to the dyebath, the cotton yarn being occasionally turned. The dyebath is kept at 60 C. for a further 15 minutes. The cotton is then removed, washed with water and dried. It is, bright yellow in shade. The dyeing possesses good fastness to washing and open soda boiling, being similar in these respects to dyeings of Caledon Yellow G (Colour Index No. 1241) Example 2 5 parts of di(ch1oromethy1)-4:4'-di(6-methyl benzthiazyl-2) -azobenzene are added to 25 parts of tetramethyl thiourea with stirring at -90 C. The mixture is stirred during a further minutes at this temperature. The yellow solution so obtained is poured into 200 parts of acetone. The suspension is filtered and the filtercake washed with acetone. 7 The product is dried in the air. The dyestufi is obtained as a bright 2,36,428 3 4 yellow powder. It dyes cotton a bright yellow methylcyclohexylamine; each X is one of the shade from a dyebath containing mild alkali as group consisting of hydrogen, methyl and ethoxy; described in Example 1. Similar dyestuffs are and wherein the CH2 group and chlorine are obtained by using di(chloromethyl) -4:4'-di(benz joined to a nitrogen of R. thiazy1-2)-azobenzene and di(chloromethyl)- 2. A compound in accordance with claim 1 4:4'-di(6-ethoxybenzthiazyl-2) azobenzene inin which X is methyl.

stead of di(chloromethyl)a4:4'-di(6-methylbenz- 3. The compound in accordance with claim 1 thiazyl-2) -azobenzene. in which X is methyl and R is the radical of pyr- Emample 3 lame 4. The compound in accordance with claim 1 5 p ts of 011 (c omethyl) -4:4'-d1(6-me in which X is methyl and R is the radical of tetbenzthiazyl-Z)-azobenzene are added to parts ramethyl-thiourea, of benzyl alcohol and 1.75 parts of triethylamine. 5, he compound in accordance with claim 1 The mixture is heated at C. for four hours, in which X is methyl and R is the radical f then cooled and poured into 200 parts of acetone. 5 me'thylcyclo-hexylamifle, The solution is poured slowly into a large volume 6. The process of manufacturing an azo dyeof ether. The precipitated solid isfiltered off, stufi which dyes cotton in shades of yellow which washed with ether and dried in the air. A yellow comprises making a mixture comprising a terp r 8 t n d. It may be used to dye cotton tiary base or" the group consisting of pyridine, tet as e cri ed inE pl 20 ramethylthiourea, triethylamine and dimethyl- Example 4 cyclohexylaiginetgnd di (0)111010g16th31) -4,4'-di( 6- 0 substitutedenz iazyl-Z -azo enzene in which beiitliiyifziiiittittt iii;iit i fi't iiit egegge $5 3.31 23.;

51851 g 0 r0ge., l'l of f3*ethoxy ethanol PaIItS of dlmethylcy; 25 heating the mixture to reaction temperature unclohexylamme. The mixture is heated at til a quaternary compound is formed I C. for two hours. The product is cooled and NORMAN HULTON HADDOCK poured into 200 parts of acetone. The solution CLIFFORD WOOD is then poured into 200 parts of benzene. The precipitated solid is filtered ofi, washed with benzene and dried in the air. The dyestufi is obtained as a yellow powder. It dyes cotton a bright yellow shade using a dyebath containing O REFERENCES CITED The fo lowing references are of record in the file of this patent:

a mild alkali, as described in Example 1. UNITED STATES PATENTS We claim: 5 1. A quaternary compound represented by the Number Name Date formula. 2,368,657 Haddock Feb. 6, 1945 x f S X,

J c1 2 N N wherein R is one of the group consisting of pyr- 2,368 658 Haddock Feb. 6, 1945 idine, tetramethylthiourea, triethylamine and di- 2,384,283 Conrad Sept, 4, 1945 

